The author's previous article was intended to demonstrate that research on intellective sex differences (SDs) was incomplete because of a general preoccupation with SDs in means. SDs in central tendency and SDs in variability must be considered together to comprehend differences between male and female distributions in abilities. (SLD)

The hypothesis of greater male variability in test results is discussed in its historical context, and reasons feminists have objected to the hypothesis are considered. The hypothesis acquires political importance if it is considered that variability results from biological, rather than cultural, differences. (SLD)

Sex differences in variability in the national norms of the Differential Aptitude Tests, Preliminary Scholastic Aptitude Test/Scholastic Aptitude Test, Wechsler Adult Intelligence Scales, and California Achievement Tests were examined. Compared to females, males were consistently more variable in quantitative reasoning, spatial visualization,…